权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Characteristics of Flowfield and Output Power of a Supersonic Flow Chemical Oxygen-Iodine Laser

超音速流化学氧碘激光器的流场和输出功率特性

基本信息

批准号：
10450075
负责人：
MASUDA Wataru
金额：
$ 3.33万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Possibility of mixing enhancement of iodine with singlet oxygen by means of acoustic excitationwas examined using a jet-diffusion flame of methane. The jet-diffusion flame was acoustically excited by monotone sound wave generated by a loud speaker. Applying the acoustic excitation using a specific range of frequency that corresponds to the Strouhal number St=0.15 to 0.6, the jet diffusion flame has peculiar features. In the mode of increasing the jet velocity, the flame shortens its original length and widened in the incident direction of sound wave. Decreasing the jet velocity, the jet velocity at which the reattachment of lifted flame occurs is lowered significantly owing to the acoustic excitation, and the lifted flames with elliptical cross sections or branched tips are discovered in the specific region of the velocity and sound frequency.A Q-switched supersonic flow chemical oxygen-iodine laser is also simulated by solving the gas flow model coupled with the precis e chemical kinetic model and the optical model. The model includes the effects of hyperfine relaxation and velocity cross relaxation for iodine atoms. The effects of such relaxations and nonuniformity of the three-dimensional flow field on the power extraction were discussed. The results show that the peak power under the influence of hyperfine relaxation and velocity cross relaxation, which is normalized to the corresponding continuous wave value, is 15. It agrees fairly well with common experimental results of Q-switched chemical oxygen-iodine laser operation. The peak power of the pulse in the three-dimensional flow field is considerably small compared to that in the equivalent one-dimensional flow field and the pulse is widened roughly twice due to insufficient mixing, shock waves, expansion waves and wakes.

本文用甲烷射流扩散火焰研究了声激发增强碘与单线态氧混合的可能性。扬声器产生的单调声波对喷射扩散火焰进行声学激发。应用使用对应于Strouhal数St=0.15至0.6的特定频率范围的声激励，射流扩散火焰具有独特的特征。在提高射流速度的方式下，火焰的初始长度缩短，沿声波入射方向的宽度变宽。降低射流速度，由于声激励，发生离焰再附着的射流速度显著降低，在特定的速度和声频区域发现了椭圆形截面或分叉尖端的升力火焰。通过求解气体流动模型，耦合精确的化学动力学模型和光学模型，对碘激光器进行了数值模拟。该模型考虑了碘原子的超精细弛豫和速度交叉弛豫效应。讨论了三维流场的弛豫和非均匀性对功率提取的影响。结果表明，在超精细弛豫和速度交叉弛豫的影响下，归一化到相应连续波值的峰值功率为15。这与调Q氧碘化学激光运转的一般实验结果符合得相当好。在三维流场中的脉冲的峰值功率是相当小的相比，在等效的一维流场中的脉冲被加宽约两倍，由于不充分的混合，冲击波，膨胀波和尾流。